"FILE - This Feb. 10, 2013 file photo shows Marcus Mumford accepting the award on stage for album of the year for ""Babel"" by Mumford & Sons at the 55th annual Grammy Awards in Los Angeles. Paul McCartney and Mumford & Sons are among the headliners for the 2013 Bonnaroo Music & Arts Festival in Manchester, Tenn. The four-day festival, held on a rural 700-acre farm, will be held June 13-16, 2013. (Photo by John Shearer/Invision/AP, file)"
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